Bleached Coraline

[ColinD]

So came home from work last night to find the majority of my coraline bleached out? It was looking okay this morning, I will admit that I had missed a weekly water change last week and when I tested params Kh was 8 but Cal was over 580 (I stopped adding drops at 29 on my API test kit), and SG was 1.028.

Not sure whats going on here, just did a water change, SPS look fine, good colour and polyp extension, but the tank definitely looks strange without coraline.

Colin